Refrigerating apparatus



June 19, 1956 J. D. OLCOTT 2,751,145

REFRIGERATING APPARATUS Filed Oct. 21, 1952 IN VEN TOR.

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2,151,145 Ice Patented June 19, 1956 REFRIGERATING APPARATUS James D. Olcott, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application October 21, 1952, Serial No. 316,009

2 Claims. (Cl. 230-58) This invention relates to refrigerating apparatus and more particularly to a sealed motor-compressor unit having an oil pump for supplying lubricant to the compressor bearings.

It is an object of this invention to provide a simple and inexpensive oil pump which is operable irrespective of the direction of rotation of the drive shaft.

More particularly it is an object of this invention to provide a vane type rotary pump in which the cylinder automatically shifts in response to a change of direction of rotation of the drive shaft so as to provide the proper porting arrangement.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a vertical sectional view somewhat diagrammatic showing the preferred embodiment of the invention;

Figure 2 is a fragmentary end elevational view, with parts broken away, showing the relative position of the parts when the shaft is operating in a counterclockwise direction; and,

Figure 3 is a sectional view on an enlarged scale taken substantially on line 33 of Figure l and showing the relative position of the parts when the drive shaft is rotating in a clockwise direction.

For purposes of illustrating the invention the oil pump has been shown applied directly to the end of a crankshaft of a reciprocating type of compressor whereas it is equally applicable to other types of compressors.

Referring now to Figure 1 of the drawing, reference numeral designates a main housing which serves to enclose an electric motor 12 having a rotor 14 secured to one end of an eccentric shaft 16 which operates a pair of conventional ported pistons 18. The pistons are caused to reciprocate by means of the eccentric straps and piston rods 20 in accordance with well known practice. A body of oil 22 is provided in the lower portion of the housing It) for supplying lubricant to the motor-compressor bearings. Reference numeral 24 designates the suction line which is adapted to be connected to the outlet of an evaporator, not shown, of a conventional refrigerating system. In the particular arrangement shown all of the fluid flowing through the system passes through the housing 14}. The compressed refrigerant discharges into the chamber 26 formed in the cylinder head of the compressor from whence it flows into a condenser, not shown. The construction thus far described is intended to represent a conventional sealed motor-compressor unit.

The motor 12 is a conventional type of polyphase motor which will operate in either direction of rotation depending upon the phase relationship of the power source. In many installations it is impossible to determine the phase relationship of the power source and consequently it is desirable to use a compressor which will operate equally well irrespective of direction of rotation of the motor as it is impossible to know which way the motor will rotate. Conventional reciprocating refrigerant compressors will operate equally well irrespective of the direction of rotation of the crankshaft but most types of simple rotary oil pumps will only operate properly in the one direction. The oil pump shown herein is designed to operate equally well in either direction of rotation of the compressor.

As best shown in Figures 2 and 3 of the drawing, the oil pump comprises a rotor 40 which is keyed directly to one end of the shaft 16 so as to rotate therewith. A pair of conventional vanes 42 are adapted to be slidably carried by the rotor 40 as shown and are biased into sliding engagement with the inner wall of the cylinder 44 by means of springs 46.

The cylinder 44 is rotatably supported within a recess in the end plate 48 of the compressor housing 10 so as to enable the cylinder to be shifted a limited amount for the purpose of shifting the inlet and outlet ports as explained hereinafter. The extent of rotation of the cylinder 44 is limited by the stationary pin 50 which is carried by the end plate 44 and which extends into a slot 52 formed in the cylinder 44 as best shown in Figure 3. The cylinder 44 is provided with one inlet port 54 which communicates with an elongated slot or cut away portion 56 in the outer periphery of the cylinder 44. The length of the slot 56 is such that irrespective of the position of the cylinder 44 it will always be in communication with the oil inlet passage 58 formed in the end plate 48. A pair of outlet ports 69 and 62 are provided in the cylinder wall 44 as shown for selective alignment with the oil outlet passage 66. The port 60 serves as the outlet port when the shaft 16 rotates in a clockwise direction as viewed in Figure 2 and the port 62 serves as the outlet port when the shaft rotates in the counterclockwise direction. The frictional resistance between the outer ends of the vanes 42 and the cylinder wall 44 is suflicient to cause automatic shifting of the cylinder 44 so that irrespective of direction of rotation of the shaft, the correct outlet ports will line up with the oil passage 66.

The oil inlet 58 is provided with a conventional check valve which allows free flow of oil upwardly through the passage 58 but prevents reverse flow of oil so as to maintain the oil pump primed at all times. Inasmuch as any form of check valve may be used the details of construction of the check valve are believed to be immaterial to the invention and therefore will not be described in greater detail.

The oil feed passage 68 in the main crankshaft 16 may be formed by drilling a longitudinal extending passage throughout the full length of the shaft 16 and then inserting a stopper in the one end of the passage and inserting a perforated plug 82 having a restricted passage in the other end of the shaft. Radial oil passages such as the oil passages 80 and 84 feed oil under pressure from the oil feed passage 68 to the various bearings to be oiled. By virtue of this construction surplus lubricant may escape through the restricted passage in the plug 82 after an adequate supply of lubricant has been fed to the various bearings.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In a sealed motor-compressor unit, a main housing having an oil pump recess in its one vertically disposed wall, a motor stator supported by said housing, a horizontally disposed shaft journaled in said housing, a motor rotor Secured to said shaft, compressor means in said housing including reciprocating impeller means, means whereby rotation of said shaft causes reciprocation of said impeller means for compressing a gas, said housing including an oil reservoir spaced downwardly from said horizontally disposed shaft, oil feed passages in said shaft, an oil pump adjacent one end of said shaft for forcefully pumping oil from said reservoir to said oil feed passages, said oil pump comprising a rotor drivingly connected to said shaft and a rotatable cylinder in said recess surrounding said rotor and coextensive axially with said rotor, a pair of diametrically opposed impeller means carried by said rotor arranged to frictionally engage said cylinder so as to urge said cylinder to rotate, means for limiting the rotation of said cylinder within said recess, said wall having first passage means extending from its bottom edge to said pump recess for conveying oil from said reservoir to said recess, the lower portion of said first passage having an enlargement therein, a check valve disposed in said enlargement, said wall having a second passage leading from said oil reservoir to the inlet side of said check valve, means for closing the lower end of said first passage and for holding said check valve in place, said cylinder having a radially extending inlet port arranged in communication with said first passage means at all times, third passage means for conveying oil from said recess to the oil feed passages formed in said shaft, and a pair of radially extending outlet ports provided in said cylinder for selective alignment with said second passage means.

2. In a sealed motor-compressor unit, a main housing having an oil pump recess in its one wall, a motor stator supported by said housing, a shaft journaled in said housing, a motor rotor secured to said shaft, compressor means in said housing including reciprocating impeller means, means whereby rotation of said shaft causes reciprocation of said impeller means for compressing a gas, said housing including an oil reservoir, oil feed passages in said shaft, an oil pump for forcefully pumping oil from said reservoir to said oil feed passages, said oil pump comprising a rotor drivingly connected to said shaft and a rotatable cylinder in said recess surrounding said rotor and coextensive axially with said rotor, a pair of diametrically opposed impeller vanes carried by said rotor arranged to frictionally engage said cylinder so as to urge said cylinder to rotate, means for limiting the rotation of said cylinder within said recess, said wall having first passage means for conveying oil from said reservoir to said recess, said cylinder having a radially ex tending inlet port in its lower side arranged in communication with said first passage means at all times, said wall having second passage means for conveying oil from said recess to the oil feed passages formed in said shaft, a pair of radially extending outlet ports provided in the upper portion of said cylinder for selective alignment with said second passage means.

References Cited in the file of this patent UNITED STATES PATENTS 861,626 Young July 30, 1907 2,128,330 Schlitz Aug. 30, 1938 2,192,654 Simons Mar. 5, 1940 2,414,187 Borsting Jan. 14, 1947 2,465,887 Larsh Mar. 29, 1949 2,668,004 Browne Feb. 2, 1954 

